Flow rate using HERMs

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drksky

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When doing the mash recirculation using a herms system, how fast do you have the wort flowing back into the tun? I imagine that having it going full bore will upset the grain bed too much (or stick the mash), but too slow and you've had problems maintaining and ramping the mash temperature.
 

BrokenHorn

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I run mine wide open and have not had a stuck mash. The HERMS coil and other fittings/hoses create enough back pressure that it's only flowing at about 2gpm using chugger pumps.
 

schaez

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I use full flow unless there is noticeable pressure drop across the false bottom. I use a Blichmann mash tun and on most batches it handles the mash without any issues. Sometimes with a lot of rye or wheat I need to back off some. I'm still able to maintain temps though. I due recirc water in the HLT to help with the heat exchange on the HERMS coil
 

dobes

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I usually start off a bit slow then work it up to full flow. Only had issues once when I was doing a pumpkin beer I kept getting pluggage issues but for the most part full flow for me.
 

emyers

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I have a full bottom keggle false bottom, I typically add about a lb of rice hills to every 11 gal batch and a bit more with wheat and rye. I run full bore with my chugger as well.
 

BadNewsBrewery

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I have experienced NUMEROUS stuck mashes and have finally worked out the kinks, I think. I add about a quarter of my grain and a pound of rice hulls, then add the remainder of the grains and stir to make sure everything is in contact with the water. I recirculate at low speed, maybe 1/3 valve, for the first minute or so and then ramp up to full valve. If you watch the level of the liquid in your mash tun, you'll know you have a problem when the level starts to rise. If wort isn't trickling through the grain bed fast enough and down through the valse bottom (I use a NorCal / J-Bird false bottom in a 10gal round cooler) then you'll see the wort level above start to increase. You may also notice your pump starting to draw a vacuum, and air may leak into the system through your fittings or hoses as the pumps aren't designed to 'suck' the wort through the grain bed. If that happens, you're stuck with shutting down the pump, stirring the mash until all the air bubbles up through it, and then starting over.

Rice hulls and a slightly 'thinner' mash (more water / # of grain) helps a lot. I may also have my grain milled slightly too fine, but it's done at the LHBS and I ask them to run it through whichever of their mills gives the finest crush.
-Kevin
 

emyers

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Badnewsbrewery, you may want to invest in a grain mill or just ask the LHBS do a normal crush.
 

burdbrew

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I have experienced NUMEROUS stuck mashes and have finally worked out the kinks, I think. I add about a quarter of my grain and a pound of rice hulls, then add the remainder of the grains and stir to make sure everything is in contact with the water. I recirculate at low speed, maybe 1/3 valve, for the first minute or so and then ramp up to full valve. If you watch the level of the liquid in your mash tun, you'll know you have a problem when the level starts to rise. If wort isn't trickling through the grain bed fast enough and down through the valse bottom (I use a NorCal / J-Bird false bottom in a 10gal round cooler) then you'll see the wort level above start to increase. You may also notice your pump starting to draw a vacuum, and air may leak into the system through your fittings or hoses as the pumps aren't designed to 'suck' the wort through the grain bed. If that happens, you're stuck with shutting down the pump, stirring the mash until all the air bubbles up through it, and then starting over.

Rice hulls and a slightly 'thinner' mash (more water / # of grain) helps a lot. I may also have my grain milled slightly too fine, but it's done at the LHBS and I ask them to run it through whichever of their mills gives the finest crush.
-Kevin
I have had the same exact issues with sparges sticking in the same manner you describe, with the pump starting to draw air and struggle to circulate. My mill is definitely tight, the grain definitely is packed in the tun. I tried pumping slow, I tried pumping fast, but the problem persists. I will try your way to the tee, see if I can make it work...
 

Yooper

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I had a lot of grainbed compaction issues in the past, with different false bottoms and different setups, even using rice hulls, with my HERMS. About four batches ago, I added a BIAB bag from Wilserbrewer, and it's been awesome. No stuck mash or sparges no matter how fast I go. I set the bag on top of the false bottom (I have a bottom draining MLT and a Jaybird false bottom) and it's been working great.

It also makes cleaning so much easier- no small pieces of grain in or under my false bottom or into any of my tubing or pumps.

I run pretty fast now, since the grainbed doesn't compact.
 

BadNewsBrewery

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I will try your way to the tee, see if I can make it work...
If it works, you're welcome. If it doesn't... then I take no ownership and clearly you did something wrong. :p Let us know how it works.

About four batches ago, I added a BIAB bag from Wilserbrewer, and it's been awesome. No stuck mash or sparges no matter how fast I go... I run pretty fast now, since the grainbed doesn't compact.
Yooper, do you find you get the same efficiencies as before? It seems that only adding a bag wouldn't somehow reduce the compaction of the grains, unless it is also allowing some of the wort to flow around the outside of the bag, which I guess would reduce mash efficiency. If the bag really is the solve all, without a drop in numbers, then count me in for trying! :ban:

-Kevin
 

Yooper

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If it works, you're welcome. If it doesn't... then I take no ownership and clearly you did something wrong. :p Let us know how it works.



Yooper, do you find you get the same efficiencies as before? It seems that only adding a bag wouldn't somehow reduce the compaction of the grains, unless it is also allowing some of the wort to flow around the outside of the bag, which I guess would reduce mash efficiency. If the bag really is the solve all, without a drop in numbers, then count me in for trying! :ban:

-Kevin
yes, same efficiencies. The bag is open, and just clipped at the top to the MLT. So the grain is very fluid and loose. It works well, and one of the things I noticed is I no longer get 'suction' and the pump cavitating. When it seems to not want to run after I mash in, I pull up the bag at the sides, and I can hear the liquid 'glog, glog' into the bottom drain. I think that even with the Jaybird false bottom and stand, that the small bottom drain was somehow causing a vacuum.

Every brewday, I"d have to blow into the tubing to get it to clear- now no longer!

After a few times, I switched over to batch sparging (so much faster with a 10 gallon batch) and my efficiencies have been a little lower now, but not by that much so I will continue.
 

augiedoggy

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If it works, you're welcome. If it doesn't... then I take no ownership and clearly you did something wrong. :p Let us know how it works.



Yooper, do you find you get the same efficiencies as before? It seems that only adding a bag wouldn't somehow reduce the compaction of the grains, unless it is also allowing some of the wort to flow around the outside of the bag, which I guess would reduce mash efficiency. If the bag really is the solve all, without a drop in numbers, then count me in for trying! :ban:

-Kevin
I would think the reason for you stuck sparges shouldn't be compaction of the grain bed but rather plugging of your false bottom or bazooka tube...
I find it odd that our experiences have been so different and wonder what the key factor is for this. I have only once had a stuck sparge in over 35 brew sessions now, during this time I used both pre ground grain and later milled my own with two different mills I used 4 different false bottom/straining methods (always using a 2 stage method with a finer strainers under the course false bottom).

last night I made a 10 gallon porter and did actually experience what I though was slower flow during the recirculation of my mash. I ordered a flow meter/rotometer right after I finished the brew so I can see how well or poorly my flow is since I use a rims tube.
I use a 3gpm 24v pump usually at full flow after starting it very slowly and ramping it up over the course of a few minutes.
The porter had a original gravity of 1.066 and the recipe stated the expected Og would be 1.058 at 75% efficiency so I must be doing something right.
 

BadNewsBrewery

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Well then - looks like I'll be bagging the next batch I have going in this weekend and see how it works!
 

JoshuaW

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I would think the reason for you stuck sparges shouldn't be compaction of the grain bed but rather plugging of your false bottom or bazooka tube...
I find it odd that our experiences have been so different and wonder what the key factor is for this. I have only once had a stuck sparge in over 35 brew sessions now, during this time I used both pre ground grain and later milled my own with two different mills I used 4 different false bottom/straining methods (always using a 2 stage method with a finer strainers under the course false bottom).

last night I made a 10 gallon porter and did actually experience what I though was slower flow during the recirculation of my mash. I ordered a flow meter/rotometer right after I finished the brew so I can see how well or poorly my flow is since I use a rims tube.
I use a 3gpm 24v pump usually at full flow after starting it very slowly and ramping it up over the course of a few minutes.
The porter had a original gravity of 1.066 and the recipe stated the expected Og would be 1.058 at 75% efficiency so I must be doing something right.

Which meter did you go with? I like the idea of using one to ensure that everything is flowing correctly with my RIMS tube.
 

BadNewsBrewery

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Well, as promised - tried the bag method this weekend with a 10gal batch. 24# of grain and as much water as I could fit in the 10gal cooler. Ramped up the pump as normal, started sucking air within the first 5-10 minutes. The upshot - very easy to fix with the bag, but didn't fix the issue. I did find my efficiency was unaffected though, which is a plus.

I will go back to my previous technique of adding rice hulls for cheap insurance.

Or maybe it's time to design an automated stir system like the big breweries use... hmmm....
 

augiedoggy

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Well, as promised - tried the bag method this weekend with a 10gal batch. 24# of grain and as much water as I could fit in the 10gal cooler. Ramped up the pump as normal, started sucking air within the first 5-10 minutes. The upshot - very easy to fix with the bag, but didn't fix the issue. I did find my efficiency was unaffected though, which is a plus.

I will go back to my previous technique of adding rice hulls for cheap insurance.

Or maybe it's time to design an automated stir system like the big breweries use... hmmm....
So what else are you doing differently that gives you such trouble? could it be your flow is just too high? I get over 80% efficiency almost regularly with my lower flow pumps which Id say only pump about 1 to 1.5 gallons a minute after the restrictions so based on that you surely dont need high flow which is more likely to cause stuck sparges for any functional reason. I've never had to use rice hulls yet...
 

BadNewsBrewery

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No clue - I've never measured the flow rate I'm getting on my chugger pumps. With the rice hulls I get upwards of 90% mash efficency and mid 80s overall when using rice hulls so I'm not stressed about it. An extra $1 or so per batch isn't a big deal. Though I still really want to design an agitating arm to fit in the system... Time to get to the garage!
 

burdbrew

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yes, same efficiencies. The bag is open, and just clipped at the top to the MLT. So the grain is very fluid and loose. It works well, and one of the things I noticed is I no longer get 'suction' and the pump cavitating. When it seems to not want to run after I mash in, I pull up the bag at the sides, and I can hear the liquid 'glog, glog' into the bottom drain. I think that even with the Jaybird false bottom and stand, that the small bottom drain was somehow causing a vacuum.

Every brewday, I"d have to blow into the tubing to get it to clear- now no longer!

After a few times, I switched over to batch sparging (so much faster with a 10 gallon batch) and my efficiencies have been a little lower now, but not by that much so I will continue.
So today I did just what Yooper does. I mashed with the bag (Wilser set me up). My experience was very similar to what Yooper describes. I had some of the same issues with suction at first. I had to pull the bag up a couple of times to get it going again, but after doing this 3 times, I had no further issues. My efficiency was spot on expectations. And the bag sure does make everything easier to clean too.
 
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